1. Field of the Invention
This invention pertains to an electroformed mask. More particularly, this invention pertains to such a mask for use in providing a coating to an end of an optical fiber.
2. Description of the Prior Art
Commonly assigned and copending U.S. patent application Ser. No. 07/467,748 filed Jan. 19, 1990, teaches an optical switch having a plurality of optical fibers bundled in an array and centrally positioned within a ferrule. A switch includes two such ferrule/fiber array assemblies. The assemblies are positioned with their end faces opposing one another and with one assembly rotatable relative to the other. As shown in the aforementioned patent application, in a preferred embodiment, the arrays of one surface are provided with a concave depression. The opposing array is provided with a convex protrusion. The purpose of the cooperating concave/convex design is, in part, to reduce or eliminate back reflection.
In using optical fibers in the telecommunications industry, it is well known to provide the fiber ends with an anti-reflective coating. Such coatings are typically minute layers of a glass dielectric. A common thickness for an anti-reflective coating may be about 1 micron deposited on the end of a fiber.
When depositing an anti-reflective coating on the end of a fiber array such as that shown in the aforementioned U.S. patent application Ser. No. 07/467,748, it is desirable not to deposit a coating on the ferrule surface which will abut against a ferrule surface of an opposing ferrule/fiber array assembly. If an anti-reflective coating were to be placed on abutting surfaces, the coating would be ground off during operation of the switch. This would create debris which could reduce the optical effectiveness of the switch. It is an object of the present invention to provide a mask for use in applying a coating on a fiber array.